The cost of keeping Chicago's streets safe has far-exceeded the police department's budget and the tab for overtime is $60 million dollars over budget.

Chicago will spend nearly three times more than expected on police overtime this year, leaving some aldermen wondering why the city doesn't use the extra money to hire more cops.

Somewhat stunned aldermen heard Superintendent Garry McCarthy explain that deploying officers to the most violent, high-crime areas this year has caused overtime costs to soar to $93 million, over $60 million more than was budgeted.

"We made a decision last year to kick off Operation Impact through overtime," McCarthy said.

"An organization the size of the police department should have a three to three and a half per cent overtime budget," said 22nd Ward Alderman Ricardo Munoz. "We're looking at a 10 percent overtime budget here."

Mayor Rahm Emanuel's administration contends that hiring for the 12,538-member police department is keeping up with retirements. McCarthy cited falling citywide crime statistics as proof his force is large enough with no need for state police help.

"They cover the highways and we cover the neighborhoods," he said. "I'm not willing to cede that quite frankly."

The police union disputes McCarthy's manpower number insisting the department is understaffed.

"Certain officers that are on long term leave of absences and they're still being carried on the manpower roll," said Michael Shields, Fraternal Order of Police.

The overtime and staff questions come as aldermen consider ways to reduce Chicago's $340 million deficit.

Downtown Alderman Brendan Reilly said the city should allow more private sources, companies, charities or wealthy individuals, to pay off-duty officers to work extra hours.

"The idea here would be to create geographies around the city, not just downtown, where you can raise private, charitable funds to hire back cops," Reilly said.

The city currently allows motion picture companies to reimburse the city for police detailed to direct traffic and secure locations.

This is not the same as an off-duty cop working a security job.

When a private source pays the city for police service, the officer wears his uniform to work and retains his full police power on the public way.